Mold for the end of concrete pipe and the like



Feb. 3, 1959 K. E. JAMES 2,871,541

MOLD FOR THE END OF CONCRETE PIPE AND THE LIKE Filed July 29, 1957 MDLD FOR THE END OF CONCRETE PIPE AND THE LIKE Kenneth E. James, Baldwin Park, Calif., assignor to United Concrete Pipe Corporation, Baldwin Park, Califi, a corporation of California Application July 29, 1957, Serial No. 674,686

6 Claims. (Cl. 25--127) This invention relates to improvements in molds for concrete pipe and the like. considered as a continuation-in-part of the subject matter disclosed in my copending application Serial No. 460,016, filed October 4, 1954.

Explanatory of the present invention, some concrete pipe, particularly large sizes, are molded in a vertical mold which, after the mold is filled with concrete is vibrated to work out air bubbles and to compact the con crete into as dense a mass as possible. After the concrete has been molded and has set sufficiently to enable the mold to be removed, the mold is removed and the molded concrete pipe is allowed to cure. used for this purpose are diametrically split and canbe opened when it is desired to remove the mold from the molded concrete pipe. Other molds are unsplit and are stripped vertically from the pipe section.

In molding concrete pipe in this manner, one customary procedure is to mold the pipe with the bell end down and the spigot end up. It is desirable to form on the exterior of the spigot a circumferentially extending This groove is intended to ultimately receive.

groove. a rubber gasket ring or the equivalent when the spigot is inserted into the bell of an adjoining pipe section in assembling sections of concrete pipe to form a pipeline.

A primary object of the present invention is to provide a means for shaping the spigot end of a molded concrete pipe so as to core in the exterior of the spigot the groove which will ultimately receive the gasket. To this end, an elastic rubber ring is positioned in the top of the mold which has an internal rib or bead which will core in the spigot the circumferential groove. As these molds are rather rapidly filled with concrete at their upper ends provision must be made for holding the elastic rubber ring in position and against being carried down in the mold by the concrete as it fills the mold.

An object of this invention is to provide a simple, novel, and highly advantageous means for firmly locking the elastic coring ring against axial displacement in the mold, the arrangement being such that the elastic coring ring can be unlocked from the mold so that it can be axially withdrawn from the mold along with the pipe when the mold is stripped from the pipe. After the mold has been removed from the pipe the elastic coring ring can be removed from the spigot by radially stretching it and slipping it off of the end of the spigot while in its stretched condition.

With the foregoing and other objects in view, which will be made manifest in the following detailed description and specifically pointed out in the appended claims, reference is bad to the accompanying drawings for an illustrative embodiment of the invention, wherein:

Figure l is a sectional view through the upper portion of a vertical concrete pipe mold constructed in accordance with the present invention; and

This application may be.

' nitcd States Patent ice similar reference characters designate similar parts' throughout, the improved mold consists of a mold body 10 of cylindrical shape designed to form the outer wall Some molds of the mold. Thismold body may or may not be diametrically split. Within the body there is a central or axial core 11, and the core, together with the mold body, form the inner and outer walls of the mold between which concrete is poured to form a concrete pipe section. 7

At the .top of the body there is an upstanding collar 12 the upstanding portion of which is designed to receive telescopically a sealing ring 13 in which there is a rubber sealing ring or gasket 14. The sealing ring may be attached to or formed integral with a shaping ring 15 designed to shape .the major portion of the spigot S on the concrete pipe section. The shaping ring may have radially extending arms 16 equipped with hooks 17 which are receivable downwardly through vertical grooves or slots in the. collar 12, and after having been passed therethrough by rotating the shaping rings slightly the hooks 17 may be disaligned from the slots to lock the shaping ring 15 in position on .top of the mold.

The invention concerns the manner in which a circumferentially extending groove 18 is formed on the exterior of the spigot. To this end an elastic endless coring ring 19 is provided having on the interior thereof a circumferentially extending ridge or bead 20. This elastic rubber coring ring is designed to fit in the corner between the top of the shaping ring 15 and a ring 21 welded or otherwise secured to the top thereof which provides inwardly extending flange portions 22. A split spring ring 23 which is split as at 24 is of channel-shaped cross section to-provide flange portions 25 and 26 designed to enter grooves 27 and 28 in rings 21 and 19, respectively. This ring, due to its inherent ability to expand, serves to press the elastic coring ring 19 against the interiorof the'shaping ring 15 and by reason of the flanges -25 and 26 extending into their respective grooves 27 and 28, the spring ring serves to lock the coring ring 19 "against axial displacement relatively to the mold and relatively to the shaping ring 15. I

Above the ring 21 there may be a spider 29 having radially inwardly extending spider arms 31 intended to hold the upper end of the core 11 centered or concentrically with relation to the mold body 10. A pouring cone 32 is usually positioned on top of the core serving to direct concrete as it is poured into the space between the core 11 and the shaping ring 15. The spider may be equipped with upwardly extending cars 33 by which the. mold body can be lifted from the molded concrete pipe section after the concrete has been partially set.

In forming a concrete pipe section with the improved mold the surfaces of the mold body, the shaping ring, and the core which are to come in contact with the concrete are usually oiled in conformity with conventional practice so that the concrete will not bond to these metallic parts.

The elastic coring ring 19 is positioned in the corner between the shaping ring 15 and ring 21 and the split spring ring 23 is then applied by radially deforming one end of the ring relatively to the other and overlapping the ends. The spring ring, while in its contracted con dition, is inserted into the mold so as to position its flanges 25 and 26 opposite the grooves 27 and 28, respectively. The spring ring is then released and allowed to expand and when the flanges enter their respective grooves the spring ring effectively locks the elastic coring ring against axial displacement. Concrete is then .zaternee poured into the mold and the mold filled and after the "mold has been filled it is usually subjected to vibration to work out air pockets contained in the concrete and to produce a settling of the. concrete intosas dense a mass as possible. 'Whenthe concrete has setsufiiciently to permit removal of; the mold the spring ring 23 is contfacted by causing its ends to overlap and it is removed. The entire moldstructure vcan thenbe stripped from. the concrete section by. pulling it vertically by means of the ears 33. During this removal of the mold theela'stic coring ring 19 will, of course, remain with the concrete pipesectionand spigot S by reason ofv the interlock between the rib ,20 andthegroove 18. ,If the shap ing ring 15, is-tapered asvshown this. stripping of the shaping ring from the spigot is somewhat facilitated.

iallyr stre tch'ed, due to,] its, elasticity to with- S while in its stretched condition. iThe coring ring 19 may. be ofi suchsize thatwhen in its normal or unstressed con'dition it just fitswithin the top of theshaping'ring 15. In thcialternative the cor- .ing ring 19 may be somewhat oversized-withrelation to the interior of-the shaping ring so that when the coring ring is in applied position it is in circum- :ferential compression. When of .this latter design the rib being undercircumferential. compression tends I to hug the w'al ls of the shaping ring 15 quite closely 'even though this rib is somewhat remotev fromtheerrpansion forces exerted by the spring ring 23. a From the above-described construction itwillfbeap- Qpr'eciated "that the improved mold enables. the groove "18 to be corediinto the exterior oftbe-spigotS quite readily. .'At the same time the coring ring is positively but releasably .locked in position against axial displacejto core a circumferential groove on the exterior. of the pipe, a 'split metallic .ringfengaging the top of the elastic coring ring and serving to;h el d the elastic coringring against the .walls of themold. V

2. A .vertical mold for concrete pipe andthe like having at the top thereot an 'elastic croring ring arranged Ito core'a circumferential gr oove on the exterior'of the pipe, at splitmetallic ringengaging the top of the elastic ta ge ing and s n .tehdd'theelafli coring g 4 against the walls of the mold, said elastic ring being axially Withdraw/able fromth'e'm'old Withthe molded pipe.

3. A vertical mold for concrete pipe and the like having at the top thereof an elastic coring ring provided with an internal annular rib adapted to core an annular groove in the pipe onithe exterior thereof, said mold having inwardly projecting flange portions over the elastic ring, and v a. splitspring' ring having tportionsengaging the elastic ring ands'aidiflangeportions to hold the elastic ring againstaxial displacement relative tothe mold While. the mold is 'being filled.

4. A vertical mold' for concrete pipe and the like having at the top thereof an elastic coring ring provided with an internal annular-rib adapted to-core: an annular groove in the pipe on. ihC QXteIiQI" thereof, said mold having inwardly projecting flange portions over the elastic ring, and a split spring ring having portions engaging .t e las insand ,said..fla e. po t p t d t elastic rin v. s i 11s t d pla men -re1 ye1 mo whil -themo d; is A; 1st, ir id i elast q t me being 7 ax ly W dr w ableftqma h amb w .,.n pefo lowing collapse and removal'of the spring ring.

5. A vertical rnold for concrete; pipe an d the like having at .the top fthereof aishaping ring; flange, portions extending inwardlyfrom the top of theshaping ring, an elastic coring ring positioned within the shaping ring and against said' flangefportions said elastic coring ring having anginternal annularrib adapted to core an annular groove in the pipejon the exterior, thereof, and a split spring ring; having lpo jtions engaging thev elastic wring i a a 'Jflan p9. 9n .,,t h th elas ringoagainst axial displacement .relative to the mold while "the mold is .being filled.

'6. A vertical mold for concrete pipe and the like hav ing at the top 'thereofa shaping rir1g,1 flange portions extending inwardly from ,ithe top of 'the sh aping ring, an elastic coring ring;.positioned within Qthelshapingring a i i n e. ons ai ela i orin i g having an internal annular. rib adapted tocorean annular groove in the pipe on the'exterior thereof and a ring against axial displacement relative to"'the rnold while the mold is being filled, said. elastiecoging ring i being axially'withdrawable frorn the mold with the pipe on collapse and removal. of the springring.

Referencesfljtedgiu 'the I file of patent 

